AU3816893A

AU3816893A - Composition and process for treating metal

Info

Publication number: AU3816893A
Application number: AU38168/93A
Authority: AU
Inventors: Shawn E Dolan; Gary A. Reghi
Original assignee: Henkel Corp
Current assignee: Henkel Corp
Priority date: 1992-04-01
Filing date: 1993-03-26
Publication date: 1993-11-08
Anticipated expiration: 2013-03-26
Also published as: AU667091B2; CN1078271A; EP0633951B1; ZA932181B; DK0633951T3; CA2132336A1; CN1034683C; CA2132336C; NO943659D0; EP0633951A1; US5281282A; ATE154833T1; JPH07505447A; WO1993020260A1; NO943659L; NZ251233A

Abstract

Heating an aqueous mixture of a fluoroacid such as H2TiF6 and an oxide, hydroxide, and/or carbonate such as silica produces a clear mixture with long term stability against settling of any solid phase, even when the oxide, hydroxide, or carbonate phase before heating was a dispersed solid with sufficiently large particles to scatter light and make the mixture before heating cloudy. The clear mixture produced by heating can either be mixed e with water soluble and/or water dispersible polymers that are polyhydroxyalkylamino- substituted polymers and/or copolymers of p-vinyl phenol, or with soluble hexavalent and/or trivalent chromium, to produce a composition that improves the corrosion resistance of metals treated with the composition, especially after subsequent painting.

Description

COMPOSITION AND PROCESS FOR TREATING METAL

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates to processes of treating meta surfaces with aqueous acidic compositions to increase th resistance to corrosion of the treated metal surface, ei ther as thus treated or after subsequent overcoating wit some conventional organic based protective layer. A majo object of the invention is to provide a storage stable single package treatment that can be substantially fre from hexavalent chromium but can protect metals substanti ally as well as the hexavalent chromium containing treat ments of the prior art, or can improve the stability o treatment solutions that do contain hexavalent chromium.

Statement of Related Art A very wide variety of materials have been taught i the prior art for the general purposes of the present in vention, but most of them contain hexavalent chromium o other inorganic oxidizing agents which are environmentall undesirable. The specific items of related art believed b the applicant to be most nearly related to the present in vention are noted below.

U. S. Patent 5,089,064 of February 18, 1992 to Reghi teaches a process for treating aluminum with a composition containing fluozirconic acid (H₂ZrF₆) , a water soluble or dispersible polymer of alkyl-N-2-hydroxyethyl- aminomethyl)-4-hydroxystyrene, and dispersed silica. This treatment produces excellent results, but is somewhat in¬ convenient because the treating composition is susceptible to slow settling of the dispersed silica component. In practice, this means that for best results, at least two components, one with the silica and one without, must be stored separately and mixed shortly before use.

U. S. Patent 4,963,596 of Oct. 16, 1990 to Lindert et al. teaches the use of water soluble derivatives of poly (vinyl phenol} in metal treating, including combinations of these polymer materials with dispersed silica among many other possibilities.

U. S. Patent 4,921,552 of May 1, 1990 to Sander et al. teaches treating aluminum with a composition comprising fluozirconic acid, hydrofluoric acid, and a water soluble polymer.

Published European Patent Application 0 273 698 (pub¬ lished July 6, 1988) teaches aqueous acidic treating solu¬ tions comprising trivalent metal compounds, silica, and preferably also nickel and/or fluoride ions. The counter anions for the trivalent metal cations used may be sil- icofluoride. ϋ. S. Patent 4,341,558 of July 27, 1982 to Yashiro et al. teaches treating metal surfaces with a composition con- taining a water soluble salt of zirconium and/or titanium, an inositol phosphate ester, and silica. The composition may also contain an organic binder such as poly(vinyl alco¬ hol}. ϋ. S. Patent 4,277,292 of July 7, 1982 to Tupper teaches treating aluminum surfaces with an aqueous acidic composition containing zirconium, fluoride, and vegetable tannin. ϋ. S. Patent 3,506,499 of Apr. 14, 1970 to Okada e al. teaches treating aluminum and zinc surfaces with a aqueous solution of chromic acid and colloidal silica.

S. M. Thomsen, "High-Silica Fluosilic Acids: Specifi Reactions and the Equilibrium with Silica", Jour. Amer. Che . Soc. 74, 1690-93 (1952), according to an abstrac thereof, teaches that high-silica fluosilic acids can b prepared with any desired amount of "extra" silica up to 18 % more than the composition given by the formula H_jSiF^ b dissolving hydrated silica in hydrofluoric acid. The hig silica fluosilic acids show characteristic reactions wit sodium salts and fluorides. A hypothesized chemical equi librium: 4H* + 5SiF₆"² + Si0₂ *~ 3(SiF₆-SiF₄)^"2 + 2H₂0 wa found to have an equilibrium constant of about 100 10,000.

DESCRIPTION OF THE INVENTION

Except in the claims and the operating examples, o where otherwise expressly indicated, all numerical quant ities in this description indicating amounts of material o conditions of reaction and/or use are to be understood a modified by the word "about" in describing the broades scope of the invention. Practice within the exact numeri cal limits stated is generally preferred.

Summary of the Invention It has been found that aqueous compositions comprisin (A) a component of dissolved fluoroacids of one or mor metals and metalloid elements selected from the group o elements consisting of titanium, zirconium, hafnium, boron silicon, germanium, and tin and (B) a component of one o more of (i) dissolved or dispersed forms of metals an metalloid elements selected from the group of element consisting of titanium, zirconium, hafnium, boron aluminum, silicon, germanium, and tin and (ii) the oxides hydroxides, and carbonates of such metals and metalloi elements can be converted by mixing for practical reactio times into an aqueous composition with long term stabilit against spontaneous settling or precipitation, even whe the metallic and/or metalloid elements, oxides, hydroxides, and/or carbonates present in the compositions are in the form of dispersed solids that would settle if stored for even a few days without ever having been reacted. These compositions prepared with mixing are then com¬ bined with either (i) a water soluble or dispersible poly-. mer and/or copolymer of one or more x-(N-R-N-R²-aminometh- yl)-4-hydroxy-styrenes, where x = 2, 4, 5, or 6, R¹ repre¬ sents an alkyl group containing from l to 4 carbon atoms, preferably a methyl group, and R² represents a substituent group conforming to the general formula H(CHOH)_n-, where n is an integer from 3 to 8, preferably from 4 to 6, or (ii) a composition contain hexavalent chromium, and, optionally but preferably, trivalent chromium. The resulting compo- sitions are suitable for treating metal surfaces to achieve excellent resistance to corrosion, particularly after sub¬ sequent conventional coating with an organic binder con¬ taining protective coating. The compositions are particu¬ larly useful on iron and steel, galvanized iron and steel, zinc and those of its alloys that contain at least 50 atom¬ ic percent zinc, and, most preferably, aluminum and its al¬ loys that contain at least 50 atomic percent aluminum. The treating may consist either of coating the metal with a li¬ quid film of the composition and then drying this liquid film in place on the surface of the metal, or simply con¬ tacting the metal with the composition for a sufficient time to produce an improvement in the resistance of the surface to corrosion, and subsequently rinsing before dry¬ ing. Such contact may be achieved by spraying, immersion, and the like as known per se in the art.

It should be understood that this description does not preclude the possibility of unspecified chemical interac¬ tions among the components listed, but instead describes the components of a composition according to the invention in the form in which they are generally used as ingredients to prepare such a composition. Description of Preferred Embodiments

To the extent that their water solubility is suffi¬ cient, the fluoroacid component [hereinafter sometimes denoted by "(A) "] to be reacted in a process according to one embodiment of the invention may be freely selected from the group consisting of H₂TiF₆, H^ZrF^ H_jHfF^ H₂SiF₆, H₂GeF₆,- H₂SnF₆, HBF₄, and mixtures thereof. H_jTiF^ H₂ZrF₆, H₂HfF₆, H₂SiF₆, HBF₄, and mixtures thereof are preferred; H₂TiF₆, H₂ZrF₆, H₂SiF₆ and mixtures thereof are more preferred; and H₂TiF₆ is most preferred. The concentration of fluoroacid component at the time of reaction is preferably between 0.01 and 7 moles per liter (hereinafter "M") , more preferably between 0.1 and 6 M..

The component [hereinafter sometimes denoted "(B)"] of metallic and/or metalloid elements and/or their oxides, hy¬ droxides, and/or carbonates is preferably selected from the group consisting of the oxides, hydroxides, and/or carbon¬ ates of silicon, zirconium, and/or aluminum and more pref¬ erably includes silica. Any form of this component that is sufficiently finely divided to be readily dispersed in wat¬ er may be used in a process according to one embodiment of this invention, but for constituents of this component that have low solubility in water it is preferred that the con¬ stituent be amorphous rather than crystalline, because crystalline constituents can require a much longer period of heating and/or a higher temperature of heating to pro¬ duce a composition no longer susceptible to settling. So¬ lutions and/or sols such as silicic acid sols may be used, but it is highly preferable that they be substantially free from alkali metal ions as described further below. Howev¬ er, it is generally most preferred to use dispersions of silica made by pyrogenic processes.

An equivalent of a metallic or metalloid element or of its oxide, hydroxide, or carbonate-is defined for the pur- poses of this description as the amount of the material containing a total of Avogadro's Number (i.e., 6.02X10²³) total atoms of metal and/or metalloid elements from the group consisting of Ti, Zr, Hf, B, Al, Si, Ge, and Sn. The ratio of moles of fluoroacid component (A) to total equiva¬ lents of component (B) in an aqueous composition heated ac¬ cording to one embodiment of this invention preferably is from 1:1 to 50:1, more preferably from 1.5:1.0 to 20:1, or still more preferably from 1.5:1 to 5.0:1.0. If desired, a constituent of this component may be treated on its sur¬ face with a silane coupling agent or the like which makes the surface oleophilic. According to one embodiment of the invention, an aque¬ ous composition comprising, preferably consisting essenti¬ ally of, or more preferably consisting of water and the fluoroacid component and the metallic and/or metalloid ele¬ ment(s) oxide(s), hydroxide(s) , and/or carbonate(s) compon- ent as described above is agitated for a sufficient time to produce a composition that does not suffer any visually de¬ tectable settling when stored for a period of 100, or more preferably 1000, hours. Preferably, during agitation the temperature is in the range from 25 to 100 * C, or more preferably within the range from 30 to 80 * C, and the time that the composition is maintained within this temperature is within the range from 3 to 480, more preferably from 5 to 90, still more preferably from 10 to 30, minutes (hereinafter often abbreviated "min") . Shorter times and lower temperatures within these ranges are generally better for converting compositions in which the component (B) is selected only from dissolved species and/or dispersed amor¬ phous species without any surface treatment to reduce their hydrophilicity, while longer times and/or higher tempera- tures within these ranges are likely to be needed if com¬ ponent (B) includes dispersed solid crystalline materials and/or solids with surfaces treated to reduce their hydro¬ philicity. With suitable equipment for pressurizing the reaction mixture, even higher temperatures than 100* C can be used in especially difficult cases.

Independently, it is preferred that the pH of the composition combining components (A) and (B) as described above be kept in the range from 0 to 4, more preferably in the range from 0.0 to 2.0, or still more preferably in the range from 0.0 to 1.0 before temperature maintenance as de¬ scribed above. Preferably after maintenance at a temperature as de¬ scribed above, the composition is brought to a temperature below 30^* C and then mixed with a component [hereinafter sometimes denoted "(C)"] consisting of either (1) water soluble or water dispersible polyhydroxyl alkylamino derivatives of poly(p.-hydroxystyrene} as described above and in more detail in ϋ. S. Patent 4,963,596, the entire specification of which, except to the extent contrary to any explicit statement herein, is hereby incorporate herein by reference or (2) hexavalent chromium, an optionally but preferably, trivalent chromium solutions as known per se in the art for treating metals, particularl aluminum and its alloys, to retard corrosion thereon. Suitable and preferred polymers and methods of preparin them are described in detail in ϋ. S. Patent 4,963,596. Preferably, the ratio by weight of the solids content o component (C) to the total of active ingredients of comp onent (A) as described above is in the range from 0.1 to 3, more preferably from 0.2 to 2, or still more preferabl from 0.20 to 1.6. A composition prepared by a process as described abov constitutes another embodiment of this invention. It i normally preferred that compositions according to the in vention as defined above should be substantially free fro many ingredients used in compositions for similar purpose in the prior art. Specifically, it is increasingly pre ferred in the order given, independently for each prefer ably minimized component listed below, that these compo sitions, when directly contacted with metal in a proces according to this invention, contain no more than 1.0, 0.35, 0.10, 0.08, 0.04, 0.02, 0.01, or 0.001 percent b weight (hereinafter "w/o") of each of the following con stituents: hexavalent chromium; ferricyanide; ferrocyanide anions containing molybdenum or tungsten; nitrates and oth¬ er oxidizing agents (the others being measured as their ox¬ idizing stoichiometric equivalent as nitrate) ; phosphorus and sulfur containing anions that are not oxidizing agents; alkali metal and ammonium cations; and organic compounds with two or more hydroxyl groups per molecule and a molec¬ ular weight of less than 300. The preference for minimal amounts of alkali metal and ammonium cations applies only to compositions used for processes according to the inven- tion that include drying into place on the metal surface to be treated without rinsing after contact between the metal surface and the composition containing components (A) , (B) , and (C) as described above; when a composition according to the invention is contacted with a metal surface and the metal surface is subsequently rinsed with water before be¬ ing dried, any alkali metal and ammonium ions present are usually removed by the rinsing to a sufficient degree to avoid any substantial diminution of the protective value of subsequently applied organic binder containing protective coatings. Also, the preference for minimization of the amount of hexavalent chromium present is due to the pol¬ luting effect of hexavalent chromium, and where there is an absence of legal restraints against pollution and/or sufficiently economical means of disposing of the hexaval- ent chromium without environmental damage exist, this pref¬ erence does not apply. In fact, in one specialized embod¬ iment of the invention, as already noted above, hexavalent chromium may advantageously be used to further improve corrosion resistance of the metal surface treated. Still another embodiment of the invention is a process of treating a metal with a composition prepared as describ¬ ed above. In one embodiment of the invention, it is preferred that the acidic aqueous composition as noted above be applied to the metal surface and dried in place thereon. For example, coating the metal with a liquid film may be accomplished by immersing the surface in a container of the liquid composition, spraying the composition on the surface, coating the surface by passing it between uppe and lower rollers with the lower roller immersed in a con tainer of the liquid composition, and the like, or by mixture of methods. Excessive amounts of the liquid compo sition that might otherwise remain on the surface prior t drying may be removed before drying by any convenien method, such as drainage under the influence of gravity squeegees, passing between rolls, and the like.

If the surface to be coated is a continuous flat shee or coil and precisely controllable coating techniques suc as gravure roll coaters are used, a relatively small volum per unit area of a concentrated composition may effectivel be used for direct application. On the other hand, if th coating equipment used does not readily permit precis coating at low coating add-on liquid volume levels, it i equally effective to use a more dilute acidic aqueous com position to apply a thicker liquid coating that contain about the same amount of active ingredients. In eithe case, the total amount of elements selected from the grou consisting of Ti, Zr, B, Si, Ge, Sn, that is present in th coating that is dried into place on the surface to b treated fall into the range of from 1 to 300, mor preferably from 5 to 150, still more preferably from 5 t 100, milligrams per square meter (hereinafter ofte abbreviated as "mg/m²") of surface area treated.

Drying may be accomplished by any convenient method of which many are known per se in the art; examples are ho air and infrared radiative drying. Independently, it i preferred that the maximum temperature of the metal reache during drying fall within the range from 30 to 200, mor preferably from 30 to 150, still more preferably from 30 t 75, * C. Also independently, it is preferred that th drying be completed within a time ranging from 0.5 to 300 more preferably from 2 to 50, still more preferably from to 10, seconds (hereinafter abbreviated "sec") after coat ing is completed.

According to an alternative embodiment of the inven tion, the metal to be treated preferably is contacted with a composition prepared as described above at a temperature within the range from 25 to 90, more preferably from 30 to 85, still more preferably from 30 to 60, * C for a time ranging from 1 to 1800, more preferably from 1 to 300, still more preferably from 3 to 30, sec, and the metal sur¬ face thus treated is subsequently rinsed with water in one or more stages before being dried. In this embodiment, at least the final rinse preferably is with deionized, dis- tilled, or otherwise purified water. Also in this embod¬ iment, it is preferred that the maximum temperature of the metal reached during drying fall within the range from 30 to 200, more preferably from 30 to 150, or still more pref¬ erably from 30 to 75, * C and that, independently, drying be completed within a time ranging from to 0.5 to 300, more preferably from 2 to 50, still more preferably from 2 to 10 sec after rinsing is completed.

A process according to the invention as generally de¬ scribed in its essential features above may be, and usually preferably is, continued by coating the dried metal surface produced by the treatment as described above with a sicca¬ tive coating or other protective coating, relatively thick as compared with the coating formed by the earlier stages of a process according to the invention as described above, as known per se in the art. Surfaces thus coated have been found to have excellent resistance to subsequent corrosion, as illustrated in the examples below. Particularly prefer¬ red types of protective coatings for use in conjunction with this invention include acrylic and polyester based paints, enamels, lacquers, and the like.

In a process according to the invention that includes other steps after the formation of a treated layer on the surface of a metal as described above and that operates in an environment in which the discharge of hexavalent chrom- ium is either legally restricted or economically handi¬ capped, it is generally preferred that none of these other steps include contacting the surfaces with any composition that contains more than, with increasing preference in the order given, 1.0, 0.35, 0.10, 0.08, 0.04, 0.02, 0.01, 0.003, 0.001, or 0.0002 w/o of hexavalent chromium. How¬ ever, in certain specialized instances, hexavalent chromium

5 may impart sufficient additional corrosion protection to the treated metal surfaces to justify the increased cost of. using and lawfully disposing of it.

Preferably, the metal surface to be treated according to the invention is first cleaned of any contaminants, par- o ticularly organic contaminants and foreign metal >!ines and/ or inclusions. Such cleaning may be accomplished by meth¬ ods known to those skilled in the art and adapted to the particular type of metal substrate to be treated. For ex¬ ample, for galvanized steel surfaces, the substrate is most 5 preferably cleaned with a conventional hot alkaline clean¬ er, then rinsed with hot water, squeegeed, and dried. For aluminum, the surface to be treated most preferably is first contacted with a conventional hot alkaline cleaner, then rinsed in hot water, then, optionally, contacted with 0 a neutralizing acid rinse, before being contacted with an acid aqueous composition as described above.

The practice of this invention may be further appreci¬ ated by consideration of the following, non-limiting, work¬ ing examples, and the benefits of the invention may be fur- 5 ther appreciated by reference to the comparison examples.

EXAMPLES

Test Methods and Other General Conditions

Test pieces of Type 3105 aluminum were spray cleaned for 15 seconds at 55° C with an aqueous cleaner containing 0 28 g/L of PARCO^β Cleaner 305 (commercially available from the Parker+Amchem Division of Henkel Corp. , Madison Heights, Michigan, USA) . After cleaning, the panels were rinsed with hot water, squeegeed, and dried before roll coating with an acidic aqueous composition as described for 5 the individual examples and comparison examples below.

For the first group of examples and comparison examp- les below, those according to the dry in place alternative treatment method, the applied liquid composition according to the invention was flash dried in an infrared oven that produces approximately 49* C peak metal temperature. Sa - pies thus treated were subsequently coated, according to the recommendations of the suppliers, with various commer- . cial paints as specified further below.

T-Bend tests were according to American Society for Testing materials (hereinafter "ASTM") Method D4145-83; Impact tests were according to ASTM Method D2794-84E1; Salt Spray tests were according to ASTM Method B-117-90 stand¬ ard; Acetic Acid Salt Spray tests were according to ASTM Method B-287-74 Standard; and Humidity tests were according to ASTM D2247-8 standard. The Boiling water immersion test was performed as follows: A 2T bend and a reverse impact deformation were performed on the treated and painted pan¬ el. The panel was then immersed for 10 minutes in boiling water at normal atmospheric pressure, and areas of the pan¬ el most a fected by the T-bend and reverse impact deforma- tions were examined to determine the percent of the paint film originally on these areas that had not been exfoliat¬ ed. The rating is reported as a number that is one tenth of the percentage of paint not exfoliated. Thus, the best possible rating is 10, indicating no exfoliation; a rating of 5 indicates 50 % exfoliation; etc. Specific Compositions Example 1:

5.6 parts by weight of amorphous fumed silicon dioxide 396.2 parts by weight of deionized water 56.6 parts by weight of aqueous 60 w/o fluotitanic acid 325.4 parts by weight of deionized water 216.2 parts by weight of an aqueous solution containing 10 w/o solids of a water soluble polymer (a Mannich adduct of poly{4-vinylphenol} with N-methylglucamine and formaldehyde) made according to the directions of column 11 lines 39 - 52 of U.S. Patent 4,963,596. Exam l 3 ;

58.8 parts by weight of aqueous 60 w/o fluotitanic acid

646.0 parts by weight of deionized water

5.9 parts by weight of amorphous fumed silicon dioxide 10.5 parts by weight of zirconium hydroxide

278.8 parts by weight of the 10 w/o solution of wate soluble polymer as used in Example 1.

Example 3

62.9 parts by weight of aqueous 60 w/o fluotitanic aci 330.5 parts by weight of deionized water

6.2 parts by weight of amorphous fumed silicon dioxide

358.9 parts by weight of deionized water

241.5 parts by weight of the 10 w/o water soluble polyme used in Example 1 Example 4

56.4 parts by weight of aqueous 60 w/o fluotitanic aci 2.1 parts by weight of Aerosil* R-972 (a surface treate dispersed silica) 56.4 parts by weight of deionized water 667.0 parts by weight of deionized water

218.1 parts by weight of the 10 w/o water soluble polyme used in Example 1

Example 5

58.8 parts by weight of aqueous 60 w/o fluotitanic aci 3.7 parts by weight of amorphous fumed silicon dioxid

10.3 parts by weight of zirconium basic carbonate

647.7 parts by weight of deionized water

279.5 parts by weight of the 10 w/o water soluble polyme used in Example 1 Example 6

52.0 parts by weight of aqueous 60 w/o fluotitanic aci

297.2 parts by weight of deionized water

3.3 parts by weight of amorphous fumed silicon dioxid 9.1 parts by weight of zirconium basic carbonate 273.6 parts by weight of deionized water

364.8 parts by weight of the 10 w/o water soluble polyme used in Example 1 Example 7

11.0 parts by weight of fumed amorphous silicon dioxide

241.0 parts by weight of deionized water

114.2 parts by weight of 60 % by weight aqueous fluotitan- ic acid

633.8 parts by weight of an aqueous composition prepared from the following ingredients: 5.41 % by weight of Cr0₃ 0.59 % by weight of pearled corn starch 94 % by weight water

For each of Examples 1 - 6, the ingredients were added in the order indicated to a container provided with stir¬ ring. (Glass containers are susceptible to chemical attack by the compositions and generally should not be used, even on a laboratory scale; containers of austenitic stainless steels such as Type 316 and containers made of or fully lined with resistant plastics such as polymers of tetraflu- oroethene or chlorotrifluoroethene have proved to be satis¬ factory.) In each of these Examples except Example 4, aft- er the addition of the silica component and before the ad¬ dition of the subsequently listed components, the mixture was heated to a temperature in the range from 38 - 43 * C and maintained within that range of temperatures for a time of 20 - 30 minutes. Then the mixture was cooled to a temp- erature below 30* C, and the remaining ingredients were stirred in without additional heating, until a clear solu¬ tion was obtained after each addition.

For Example 4, the Si0₂ used was surface modified with a silane, and because of its hydrophobic nature, the mix- ture containing this form of silica was heated for 1.5 hours at 70* C to achieve transparency. The remaining steps of the process were the same as for Example 1.

For Example 7, the first three ingredients listed were mixed together and maintained at 40 + 5 ' C for 10 minutes with stirring and then cooled. In a separate container, the Cr0₃ was dissolved in about fifteen times its own weight of water, and to this solution was added a slurry of the corn starch in twenty-four times its own weight of water The mixture was then maintained for 90 minutes with gentl stirring at 88 + 6 * C to reduce part of the hexavalen chromium content to trivalent chromium. Finally, thi mixture was cooled with stirring and then added to th previously prepared heated mixture of fluotitanic acid silicon dioxide, and water. This composition is used i the manner known in the art for compositions containin hexavalent and trivalent chromium and dispersed silica, bu it is much more stable to storage without phase separation

Comparative Example 1

18.9 parts by weight of aqueous 60 w/o fluotitanic aci 363.6 parts by weight of the 10 w/o water soluble polyme used in Example 1 617.5 parts by weight of deionized water Comparative Example 2

18.9 parts by weight of aqueous 60 w/o fluotitanic acid 71.8 parts by weight of the 10 w/o water soluble polym used in Example 1 909.3 parts by weight of deionized water

For Comparative Examples 1 and 2 the components we added together with agitation in the order indicated, wi no heating before use in treating metal surfaces.

Add-on mass levels, specific paints used, and te results with some of the compositions described above a shown in Tables 1 - 5 below.

TABLE 2: Panels Painted with Lilly™ Colonial White Single Coat

Pol ester

TABLE 4: Panels Painted with Valspar/Deβoto™ White Single Coat

Polyester

The storage stability of the compositions according to all of the examples above except Example 2 was so good that no phase separation could be observed after at least 1500 hours of storage. For Example 2, some settling of a slight amount of apparent solid phase was observable after 150 hours.

To obtain the results reported in the following tables, an alternative process of treating the metal surfaces according to the invention and a different aluminum alloy were used. Specifically, test pieces of Type 5352 or 5182 aluminum were spray cleaned for 10 seconds at 55* C with an aqueous cleaner containing 24 g/L of PARCO* Cleaner 305 (commercially available from the Parker+Amchem Division of Henkel Corp., Madison Heights, Michigan, USA) . After cleaning, the panels were rinsed with hot water; then they were sprayed with the respective treatment solutions according to the invention, which were the same as those already described above with the same Ex¬ ample Number except that they were further diluted with water to the concentration shown in the tables below, for 5 seconds; and then were rinsed in water and dried, prior to painting. The "0T Bend" column in the following tables reports the result of a test procedure as follows: 1. Perform a 0-T bend in accordance with ASTM Method D4145-83. 2. Firmly apply one piece of #610 Scotch* tape to the area of the test panel with the O-T bend an to the adjacent flat area.

3. Slowly pull the tape off from the bend and th adjacent flat area.

4. Repeat steps 2 and 3, using a fresh piece of tap for each repetition, until no additional paint is removed by the tape.

5. Report the maximum distance from the 0-T ben into the flat area from which paint removal i observed according to the scale below: oss - -- -

1. Expose the painted samples to steam at temperature of 120* C steam for 90 minutes in pressure cooker or autoclave. 2. Crosshatch the painted sample - two perpendicula cuts; a Gardner Crosshatch tool with 11 knif edges spaced 1.5 mm apart was used. 3. Firmly apply #610 Scotch™ tape to th crosshatched area and remove tape. 4. Examine the crosshatched area for paint no removed by the tape and report a numbe representing one-tenth of the percentage of pain remaining. 5. Using a microscope at 10 - 80 times magnification, visually observe crosshatched area for blistering, and rate size and density of blisters.

The "15 Minute Boiling DOWFAX™ 2A1 Immersion"- columns of the tables below report the results of tests performed after treatment as follows:

1. Prepare solution of 1 % by volume of DOWFAX™ 2A1 in deionized water and bring to boil.

2. Immerse painted test panels in the boiling solution prepared in step 1 and keep there for 15 minutes; then remove panels, rinse with water, and dry. DOWFAX™ 2A1 is commercially available from Dow

Chemical and is described by the supplier as 45 % active sodium dodecyl diphenyloxide disulfonate. The "Cross Hatch" test after this treatment was made in the same way as described above for steps 2 - 4 after "Ninety Minute Steam Exposure". The "Reverse Impact" test was made as described in ASTM D2794-84E1 (for 20 inch pounds impact) , then proceeding in the same way as described above for steps 3 - 4 after "Ninety Minute Steam Exposure". The "Feathering" test was performed as follows: Using a util- ity knife, scribe a slightly curved "V" on the back side of the test panel. Using scissors, cut up about 12 millimet¬ ers from the bottom along the scribe. Bend the inside of the V away from side for testing. Place sample in a vise and, using pliers, pull from the folded section with a slow continuous motion. Ignore the part of the panel between the top edges nearest to the vertex and a line parallel to the top edge but 19 mm away from it. On the remainder of the panel, measure to edge of feathering in millimeters. Record the largest value observed.

The results of tests according to these procedures are show in Tables 6 - 8 below. TABLE 6: 5182 alley panels Painted with Valspar™ S-9835002 Paint

TABLE 7 : 5352 Alloy Panels Painted with Valspar™ S-9009-139 Paint

TABLE 8: 5352 Alloy Panels Painted with Valspar™ S-9009-154 Paint

What is claimed is:

Claims

1. A process comprising steps of:

(I) providing a mixture consisting essentially of water and: (A) a dissolved component selected from the group consisting of H₂TiF₆, H_gZrF^ H_jHfF^* H₂SiF₆, H_jGeF^ H_gSnF_j, HBF₄, and mixtures thereof and (B) a dissolved, dispersed, or both dissolved and dispersed component selected from the group consisting of Ti, Zr, Hf, Al, Si, Ge, Sn, and B, the oxides, hydroxides, and carbonates of Ti, Zr, Hf, Al, Si, Ge, Sn, and B, and mixtures of any two or more of these elements, oxides, hydroxides, and carbonates;

(II) agitating the mixture provided in step (I) for at least a sufficient time at a sufficient temperature that the mixture is free from any visually observable evidence of phase separation and is sufficiently stable that it would remain free from any visually observable evidence of phase separation during storage at temperature in the range from 20 to 25 ° C for a period of at least 100 hours;

(III) mixing with the agitated mixture from the end of step (II) a component (C) selected from the group consisting of (1) water soluble and water dispersible polymers and copolymers of x-fN-R'-N- R²-aminomethyl)-4-hydroxy-styrenes, where x = 2,

3, 5, or 6; R¹ represents an alkyl group containing from 1 to 4 carbon atoms; and R² represents a substituent group conforming to the general formula H(CHOH)_n-, where n is an integer from 3 to 8 and mixtures of any two or more therof; and (2) dissolved hexavalent chromium to form a mixture that is sufficiently stable that it would remain free from any visually observable evidence of phase separation during storage at temperature in the range from 20 to 25 ^• C for a period of at least 100 hours.

2. An aqueous liquid mixture made by a process according to claim 1.

3. A process according to claim 1 comprising an additional step (IV) selected from the group consisting of: (IV.1) coating^" a metal surface with a layer of the liquid composition from the end of step (III) , said layer having a thickness such that it contains from 1 to 300 mg/m² of the metal surface of the total amount of elements selected from the group consisting of Ti, Zr, B, Si, Ge, Sn, and drying said layer of the liquid composition from the end of step (III) into place on said metal surface, without intermediate rinsing; and (TV.2) contacting a metal surface with the liquid composition from the end of step (III) at a temperature in the range from 25 to 90 ^• c for a time in the range from 1 to 1800 seconds, removing the metal surface from contact with said liquid composition from the end of step (III) , rinsing said metal surface with water, and drying the rinsed metal surface.

4. A process according to claim 1 comprising an additional step (IV) selected from the group consisting of:

(IV.1) coating a metal surface with a layer of the liquid composition from the end of step (III) , said layer having a thickness such that it contains from 5 to 100 mg/m² of the metal surface of the total amount of elements selected from the group consisting of Ti, Zr, B, Si, Ge, Sn, and drying said layer of the liquid composition from the end of step (III) into place on said metal surface, without intermediate rinsing, within a time in the range from 2 to 50 seconds after coating is completed; and

(IV.2) contacting a metal surface with the liquid composition from the end of step (III) at a temperature in the range from 30 to 60 * C for a time in the range from 3 to 30 seconds, removing the metal surface from contact with said liquid composition from the end of step (III) , rinsing said metal surface with water, and drying the rinsed metal surface within a time from 2 to 50 seconds after rinsing is completed.

5. A process according to claim 1, wherein (i) the mixture provided in step (X) contains a total amount in the range from 0.01 to 7.0 ϊ$ of material selected from the group consisting of H_jTiF^ H_gZrF^ H_jHfF_j, H_jSiF^ HBF₄, and mixtures thereof and has a ratio of moles of component (A) to equivalents of component (B) in the range from 1:1 to 50:1; (ii) during step (II) the mixture is maintained at a temperature in the range from 25 to 100 * C for a time in the range from 3 to 480 minutes; and (iii) component (C) comprises a total amount of water soluble and water disper¬ sible polymers and copolymers of x-(N-R¹-N-R²-aminomethyl)- 4-hydroxy-styrenes, where x = 2, 3, 5, or 6, R¹ represents an alkyl group containing from 1 to 4 carbon atoms, and R² represents a substituent group conforming to the general formula H(CH0H)_n-, where n is an integer from 3 to 8, such that the ratio by weight of said water soluble and water dispersible polymers and copolymers to the total weight of component (A) is in the range from 0.1:1 to 3:1.

6. An aqueous liquid mixture made by a process according to claim 5.

7. A process according to claim 5 comprising an additional step (IV) selected from the group consisting of: (IV.1) coating a metal surface with a layer of the liquid composition from the end of step (III) , said layer having a thickness such that it contains from 1 to 300 mg/m² of the metal surface of the total amount of elements selected from the group consisting of Ti, Zr, B, Si, Ge, Sn, and drying said layer of the liquid composition from the end of step (III) into place on said metal surface, without intermediate rinsing; and

(IV.2) contacting a metal surface with the liqui composition from the end of step (III) at temperature in the range from 25 to 90 ^• C for time in the range from 1 to 1800 seconds, removing the metal surface from contact with sai liquid composition from the end of step (III) , rinsing said metal surface with water, and drying the rinsed metal surface.

8. A process according to claim 5 comprising an additional step (IV) selected from the group consisting of: (IV.1) coating a metal surface with a layer of the liquid composition from the end of step (III) , said layer having a thickness such that it contains from 5 to 100 mg/m² of the metal surface of the total amount of elements selected from the group consisting of Ti, Zr, B, Si, Ge, Sn, and drying said layer of the liquid composition from the end of step (III) into place on said metal surface, without intermediate rinsing, within a time in the range from 2 to 50 seconds after coating is completed; and

(IV.2) contacting a metal surface with the liquid composition from the end of step (III) at a temperature in the range from 30 to 60 ' C for a time in the range from 3 to 30 seconds, removing the metal surface from contact with said liquid composition from the end of step (III) , rinsing said metal surface with water, and drying the rinsed metal surface within a time from 2 to 50 seconds after rinsing is completed.

9. A process according to claim 1, wherein (i) the mixture provided in step (I) contains a total amount in the range from 0.1 to 6.0 M of material selected from the group consisting of H_gTiF^ H_jZrF^ H_jSiF_g, and mixtures thereof; has a ratio of moles of component (A) to total equivalents of oxides, hydroxides, and carbonates of silicon, zirconi¬ um, and aluminum in the range from 1.5:1.0 to 20:1; and has a pH value in the range from 0 to 4; (ii) during step (II) the mixture is maintained at a temperature in the range from 30 to 80 * C for a time in the range from 5 to 90 min¬ utes; and (iii) component (C) comprises a total amount of water soluble and water dispersible polymers and copolymers of x-(N-R¹-N-R²-aminomethyl)-4-hydroxy-styrenes, where x = 2, 3, 5, or 6, R¹ represents an alkyl group containing from 1 to 4 carbon atoms, and R² represents a substituent group conforming to the general formula H(CHOH)_n-, where n is an integer from 3 to 8, such that the ratio by weight of said water soluble and water dispersible polymers and copolymers to the total weight of component (A) is in the range from 0.2:1 to 2:1.

10. An aqueous liquid mixture made by a process according to claim 9.

11. A process according to claim 9 comprising a additional step (IV) selected from the group consisting of: (IV.1) coating a metal surface with a layer of th liquid composition from the end of step (III) , said layer having a thickness such that i contains from 1 to 300 mg/m² of the metal surfac of the total amount of elements selected from th group consisting of Ti, Zr, B, Si, Ge, Sn, an drying said layer of the liquid composition fro the end of step (III) into place on said meta surface, without intermediate rinsing; and (IV.2) contacting a metal surface with the liqui composition from the end of step (III) at temperature in the range from 25 to 90 * C for time in the range from 1 to 1800 seconds, removing the metal surface from contact with sai liquid composition from the end of step (III) , rinsing said metal surface with water, and dryin the rinsed metal surface.

12. A process according to claim 9 comprising an additional step (IV) selected from the group consisting of:

(TV.l) coating a metal surface with a layer of the liquid composition from the end of step (III) , said layer having a thickness such that it contains from 5 to 100 mg/m² of the metal surface of the total amount of elements selected from the group consisting of Ti, Zr, B, Si, Ge, Sn, and drying said layer of the liquid composition from the end of step (III) into place on said metal surface, without intermediate rinsing, within a time in the range from 2 to 50 seconds after coating is completed; and

13. A process according to claim 1, wherein (i) the mixture provided in step (I) contains a total amount in the range from 0.1 to 6.0 M of material selected from the group consisting of H₂TiF₆, H₂ZrF₆, H_jSiF^ and mixtures thereof; has a ratio of moles of component (A) to total equivalents of oxides, hydroxides, and carbonates of silicon, zirconi-. urn, and aluminum in the range from 1.5:1.0 to 5:1; and has a pH value in the range from 0 to 2; (ii) during step (II) the mixture is maintained at a temperature in the range from 30 to 80 * C for a time in the range from 10 to 30 minutes; and (iii) component (C) comprises a total amount of water soluble and water dispersible polymers and copoly¬ mers of x-(N-R¹-N-R²-aminomethyl)-4-hydroxy-styrenes, where x - 2, 3, 5, or 6, R¹ represents an alkyl group containing from 1 to 4 carbon atoms, and R² represents a substituent group conforming to the general formula H(CHOH)_n-, where n is an integer from 3 to 8, such that the ratio by weight of said water soluble and water dispersible polymers and co¬ polymers to the total weight of component (A) is in the range from 0.20:1 to 1.6:1.

14. An aqueous liquid mixture made by a process according to claim 13.

15. A process according to claim 13 comprising an additional step (IV) selected from the group consisting of: (IV.1) coating a metal surface with a layer of the liquid composition from the end of step (III) , said layer having a thickness such that it contains from 5 to 150 mg/m² of the metal surface of the total amount of elements selected from the group consisting of Ti, Zr, B, Si, Ge, Sn, and drying said layer of the liquid composition from the end of step (III) into place on said metal surface, without intermediate rinsing; and (IV.2) contacting a metal surface with the liquid composition from the end of step (III) at a temperature in the range from 30 to 85 * C for a time in the range from 1 to 300 seconds, removing the metal surface from contact with said liquid composition from the end of step (III) , rinsing said metal surface with water, and drying the rinsed metal surface.

16. A process according to claim 13 comprising a additional step (TV) selected from the group consisting of (IV.1) coating a metal surface with a layer of th liquid composition from the end of step (III) said layer having a thickness such that i contains from 5 to 100 mg/m² of the metal surfac of the total amount of elements selected from th group consisting of Ti, Zr, B, Si, Ge, Sn, an drying said layer of the liquid composition fro the end of step (III) into place on said meta surface, without intermediate rinsing, within time in the range from 2 to 50 seconds afte coating is completed; and

(IV.2) contacting a metal surface with the liqui composition from the end of step (III) at temperature in the range from 30 to 60 ^• c for time in the range from 3 to 30 seconds, removin the metal surface from contact with said liqui composition from the end of step (III) , rinsin said metal surface with water, and drying th rinsed metal surface within a time from 2 to 1 seconds after rinsing is completed.

17. A process according to claim 1, wherein (i) th mixture provided in step (I) contains a total amount in th range from 0.1 to 6.0 M. of H₂TiF₆; has a ratio of moles o H₂TiF₆ to total equivalents of silicon dioxide in the rang from 1.5:1.0 to 5:1; and has a pH value in the range fro 0.0 to 1.0; (ii) during step (II) the mixture is maintaine at a temperature in the range from 30 to 80 * C for a tim in the range from 10 to 30 minutes; and (iii) component (C comprises a total amount of water soluble and water disper sible polymers and copolymers of x-{[(N-methylamino) glucamino]methyl}-4-hydroxy-styrenes, where x = 2, 3, 5, o 6, such that the ratio by weight of said water soluble an water dispersible polymers and copolymers to the tota weight of H₂TiF₆ is in the range from 0.20:1 to 1.6:1.

18. An aqueous liquid mixture made by a process according to claim 9.

19. A process according to claim 17 comprising an additional step (IV) selected from the group consisting of: (IV.1) coating a metal surface with a layer of the liquid composition from the end of step (III) , said layer having a thickness such that it contains from 5 to 150 mg/m² of the metal surface of the total amount of elements selected from the group consisting of Ti, Zr, B, Si, Ge, Sn, and drying said layer of the liquid composition from the end of step (III) into place on said metal surface, without intermediate rinsing; and

(IV.2) contacting a metal surface with the liquid composition from the end of step (III) at a temperature in the range from 30 to 85 * C for a time in the range from 1 to 300 seconds, removing the metal surface from contact with said liquid composition from the end of step (III) , rinsing said metal surface with water, and drying the rinsed metal surface.

20. A process according to claim 17 comprising an additional step (TV) selected from the group consisting of:

(IV.1) coating a metal surface with a layer of the liquid composition from the end of step (III) , s said layer having a thickness such that it contains from 5 to 100 mg/m² of the metal surface of the total amount of elements selected from the group consisting of Ti, Zr, B, Si, Ge, Sn, and drying said layer of the liquid composition from o the end of step (III) into place on said metal surface, without intermediate rinsing, within a time in the range from 2 to 10 seconds after coating is completed, while bringing the maximum metal temperature during drying to a value 5 between 30 and 75 * C; and

(TV.2) contacting a metal surface with the liquid composition from the end of step (III) at a temperature in the range from 30 to 60 ^• c for a time in the range from 3 to 30 seconds, removing 0 the metal surface from contact with said liquid composition from the end of step (III) , rinsing said metal surface with water, and drying the rinsed metal surface within a time from 2 to 10 seconds after rinsing is completed, while 5 bringing the maximum metal temperature during drying to a value between 30 and 75 * C.